Water management building wrap

ABSTRACT

The present invention provides a water management building wrap that may be useable between a frame structure of a building and an exterior building covering. In at least one embodiment, the building wrap comprises a permeable membrane and an extruded polymeric drainage structure secured to the second side of the membrane. In at least one embodiment, the drainage structure includes a plurality of generally vertical members having a first thickness and forming boundaries for generally vertical water drainage channels, and a plurality of generally horizontal members attached to the generally vertical members and having a second thickness less than the first thickness and forming integral joints at intersections of the generally vertical members and the generally horizontal members that provide dimensional stability to maintain the orientation of the generally vertical members and form stable vertical water drainage channels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/548,524 filed Oct. 11, 2006, which, in turn, claims the benefit ofU.S. provisional application Ser. No. 60/726,669 filed Oct. 14, 2005,which are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an extruded netting and to a watermanagement building wrap incorporating an extruded netting.

2. Background Art

Buildings, both residential and commercial, typically have a framestructure, a sheathing over the frame structure, and an exteriorbuilding covering over the sheathing. Building wraps have been widelyused in the construction of buildings. The building wraps are typicallyplaced between the sheathing and the exterior building covering to serveas a moisture barrier by inhibiting water intrusion into the building.These building wraps can also help to prevent energy loss by inhibitingair intrusion into the building. Popular building wraps include Tyvek®Homewrap, available from DuPont, and Typar® Housewrap, available fromBBA Fiberweb.

Water can sometimes get behind the exterior building covering throughcracks in the exterior building covering or by the window and doorjoints. Also, moisture from the relatively warm interior of the buildingcan penetrate through the sheathing and the building wrap and condenseinto water upon contacting the relatively cold exterior building cover.The water can become trapped between the building wrap and the exteriorbuilding covering, possibly causing water damage to the building. Also,trapped water can encourage growth of mold and mildew, as well as waterdamage to building components.

It would be advantageous to provide a building wrap that would not trapwater that gets between the sheathing and the exterior building coveringof a building.

SUMMARY OF THE INVENTION

The present invention relates to a plastic netting that, in conjunctionwith various building wrap membranes, provides one or more verticaldrainage paths within the exterior layers of a building envelope.

In at least one aspect, the present invention provides a watermanagement building wrap for use between a frame structure of a buildingand an exterior building covering. In at least one embodiment, thebuilding wrap comprises a permeable membrane disposable over at least aportion of the frame structure which, when disposed over the framestructure, has a first side facing the frame structure and a second sidefacing away from the frame structure. In this embodiment, the buildingwrap further comprises a drainage structure secured to the second sideof the membrane, wherein the drainage structure includes a plurality ofgenerally vertical members having a first thickness and being spacedapart from each other such that adjacent pairs of the generally verticalmembers form boundaries for a generally vertical water drainage channel.In this embodiment, the drainage structure further includes a pluralityof generally horizontal members attached to the generally verticalmembers and having a second thickness less than the first thickness. Inthis embodiment, the drainage structure is an extruded polymericmaterial forming integral joints at intersections of the generallyvertical members and the generally horizontal members, with the jointsproviding dimensional stability to maintain the orientation of thegenerally vertical members and form stable vertical water drainagechannels.

In at least another embodiment, the building wrap comprises a permeablemembrane having a first side and a second side, and an extrudedpolymeric netting structure secured to one of the sides of the membrane.In this embodiment, the netting structure includes a plurality ofgenerally vertical members having a first average thickness and beingspaced apart from each other such that adjacent pairs of the generallyvertical members form boundaries for a generally vertical water drainagechannel. In this embodiment, the netting structure further includes aplurality of generally horizontal members extending between and attachedto the generally vertical members and having a second average thicknessless than the first thickness In this embodiment, the netting structurehas integral joints at intersections of the generally vertical membersand the generally horizontal members, with the joints providingdimensional stability to maintain the orientation of the generallyvertical members and form stable vertical water drainage channels.

In at least another embodiment, the generally vertical members arespaced apart from each other with a first frequency and the generallyhorizontal members are spaced apart from each other with a secondfrequency greater than the first frequency.

In at least one embodiment, the first average thickness is 1.25 to 25times the second average thickness. In at least another embodiment, thefirst average thickness is 1.5 to 10 times the second average thickness.In at least yet another embodiment, the first average thickness is 2 to5 times the second average thickness.

In at least one embodiment, each of the joints have an average thicknessof 5 to 300 mils. In at least one embodiment, the first averagethickness of the generally vertical members is 4 to 290 mils. In atleast one embodiment, the second average thickness of the generallyhorizontal members is 0.5 to 50 mils.

In at least another embodiment, the present invention provides a watermanagement building wrap for use between a sheathing of a building andan exterior building covering. In at least this embodiment, the buildingwrap comprises a permeable membrane disposable on at least a portion ofthe sheathing, the membrane having a first side and a second side,wherein the first side, when the membrane is disposed on the sheathing,faces the sheathing, and an extruded polymeric netting structure securedto the second side of the membrane. In this embodiment, the nettingstructure includes a plurality of generally vertical members having afirst thickness and being spaced apart from each other such thatadjacent pairs of the generally vertical members form boundaries for agenerally vertical water drainage channel, and a plurality of generallyhorizontal members extending between and attached to the generallyvertical members and having a second thickness less than the firstthickness. In this embodiment, the netting structure has integral jointsat intersections of the generally vertical members and the generallyhorizontal members, with the joints providing dimensional stability tomaintain the orientation of the generally vertical members and formstable vertical water drainage channels.

In at least another aspect, the present invention also relates to amethod for making a water management building wrap. In this embodiment,the building wrap may be disposed between a frame structure or sheathingof a building and an exterior building covering, before the exteriorbuilding covering is applied. In this embodiment, the building wrap ismade by securing an extruded netting to a permeable membrane. In thisembodiment, the membrane, when the membrane is disposed between a framestructure and an exterior building covering, has a first side facing theframe structure and a second side facing away from the frame structure.In this embodiment, the netting includes a plurality of generallyvertical members having a first thickness and being spaced apart fromeach other such that adjacent pairs of the generally vertical membersform boundaries for a generally vertical water drainage channel, and aplurality of generally horizontal members attached to the generallyvertical members and having a second thickness less than the firstthickness. In this embodiment, the netting is an extruded polymericmaterial forming integral joints at intersections of the generallyvertical members and the generally horizontal members, with the jointsproviding dimensional stability to maintain the orientation of thegenerally vertical members and form stable vertical water drainagechannels.

In at least another embodiment, the positioning of the netting and themembrane could be reversed, so that the netting faces towards the framestructure while the membrane faces towards the exterior buildingcovering.

In at least another embodiment, the building wrap comprises a firstmembrane disposable on at least a portion of the sheathing, the membranehaving a first side and a second side, the first side, when the membraneis disposed on the sheathing, facing the sheathing, a second membranespaced from the first membrane, and an extruded polymeric nettingstructure between the first and second membrane. In this embodiment, thenetting structure includes a plurality of generally vertical membershaving a first thickness and spaced apart from each other such thatadjacent pairs of the generally vertical members form boundaries for agenerally vertical water drainage channel. In this embodiment, thenetting structure further includes a plurality of generally horizontalmembers extending between and attached to the generally vertical membersand having a second thickness less than the first thickness, with thenetting structure having integral joints at intersections of thegenerally vertical members and the generally horizontal members, thejoints providing dimensional stability to maintain the orientation ofthe generally vertical members and form stable vertical water drainagechannels. In this embodiment, the netting could face either towards theframe structure (or the sheathing) or towards the exterior buildingcovering. In some embodiments, when the channels face towards the framestructure this construction tends to occlude less surface area on thebreathable membrane layer thereby tending to enhance breathability.

In at least one embodiment, the members are extruded to have arectangular net configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cut-away perspective view of an embodiment of the buildingwrap of the present invention as applied to an exemplary buildingstructure;

FIG. 2 is a perspective view of a component of the building wrap of FIG.1;

FIG. 3 is a side view of the building wrap of FIG. 1;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is a cross-sectional view of an exemplary strand of the componentof FIG. 2;

FIG. 6 is a view similar to FIG. 3 illustrating another embodiment ofthe present invention; and

FIG. 7 is a view similar to FIG. 4 illustrating another embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Reference will now be made in detail to presently preferredcompositions, embodiments and methods of the present invention, whichconstitute the best modes of practicing the invention presently known tothe inventors. The Figures are not necessarily to scale. However, it isto be understood that the disclosed embodiments are merely exemplary ofthe invention that may be embodied in various and alternative forms.Therefore, specific details disclosed herein are not to be interpretedas limiting, but merely as a representative basis for any aspect of theinvention and/or as a representative basis for teaching one skilled inthe art to variously employ the present invention.

Except in the examples, or where otherwise expressly indicated, allnumerical quantities in this description indicating amounts of materialor conditions of reaction and/or use are to be understood as modified bythe word “about” in describing the broadest scope of the invention.Practice within the numerical limits stated is generally preferred.Also, unless expressly stated to the contrary: percent, “parts of,” andratio values are by weight; the term “polymer” includes “oligomer,”“copolymer,” “terpolymer,” and the like; the description of a group orclass of materials as suitable or preferred for a given purpose inconnection with the invention implies that mixtures of any two or moreof the members of the group or class are equally suitable or preferred;description of constituents in chemical terms refers to the constituentsat the time of addition to any combination specified in the description,and does not necessarily preclude chemical interactions among theconstituents of a mixture once mixed; the first definition of an acronymor other abbreviation applies to all subsequent uses herein of the sameabbreviation and applies mutatis mutandis to normal grammaticalvariations of the initially defined abbreviation; and, unless expresslystated to the contrary, measurement of a property is determined by thesame technique as previously or later referenced for the same property.

Referring to FIG. 1, a cut away perspective view of an exemplarybuilding structure 10 is illustrated. The exemplary building structure10 includes a plurality of spaced apart framing members 12 that form aframe structure. A sheathing 14 is suitably secured to the framingmembers 12. An exterior building covering 16 is secured to the sheathing14. Between the sheathing 14 and the exterior building covering 16 isdisposed a building wrap 20 made in accordance with at least oneembodiment of the present invention. In at least one embodiment thebuilding wrap 20 comprises a permeable membrane 22 and an extrudedplastic netting 24.

The frame members 12 can be made of any suitable framing material,including wood, wood composites, or metal.

The sheathing 14 may be made of any suitable material and may compriseany suitable construction, such as sheets or boards. Some examples ofsuitable materials include, but are not necessarily limited to, thincomposite laminations, fiberboard, oriented-strand board (OSB), plywood,polyisocyanurate foam, extruded polystyrene (XPS) foam and moldedexpanded polystyrene (EPS) foam. The sheathing 14 may be secured to theframe members 12 by any suitable fasteners such as nails, screws orstaples.

The exterior building covering 16 may comprise any suitable exteriorbuilding covering and may have any suitable configuration. Some examplesof suitable exterior coverings include, but are not necessarily limitedto, siding, vinyl siding, brick, stucco, stone, masonry, concreteveneers, and cement based siding planks and panels. The exteriorbuilding covering 16 can be secured to the sheathing 14 in any suitablemanner, such as by nails, screws or staples.

As shown in the embodiment illustrated in FIG. 3, the building wrap 20comprises a membrane 22 and an extruded plastic netting 24. The membrane22 has a first side 26 and an opposed second side 28. As best seen inFIGS. 3 and 4, when the building wrap 20 is secured to the sheathing 14,the first side 26 of the membrane 22 faces the exterior buildingcovering 16 while the second side 28 of the membrane 22 faces thesheathing 14. The building wrap 20 can be secured to the sheathing 14 byany suitable means, such as by nails, staples or screws. In at least oneembodiment, the membrane 22 has an average thickness of 1 to 75 mils,and in other embodiments of 5 to 40 mils.

The membrane 22 may be vapor permeable or impermeable. In embodimentswhere the membrane 22 is impermeable, the membrane may be any suitableimpermeable membrane, such as films or sheets of PP, PE or PVC or otherimpermeable weather resistant building papers.

In embodiments where the membrane 22 is vapor permeable, the vaporpermeable membrane 22 may be any suitable vapor permeable membrane thatis water resistant. The vapor permeable membrane 22 may be any suitablebreathable sheet material made of spun bonded synthetic fibers such aspolyethylene, polypropylene or polyester fibers, sheets of spunbonded-melt blown-spun bonded (“SMS”) polymer fibers (or other non-wovenfabricated products), perforated polymer films, woven slit film,microporous film laminates, and building papers. The permeable membrane22 could also be a rolled on and/or sprayed on liquid that dries orcures as a film directly on the sheathing 14. In at least certainembodiments, particularly preferred permeable membrane 22 compriseTyvek® Homewrap or Typar® Housewrap.

In at least one embodiment, the netting 24 may be secured by anysuitable securing means to the first side 26 of the membrane 22, such asby nails, staples, screws or adhesive. In another embodiment, themembrane 22 may be first secured to the sheathing 14 with the netting 24then being secured over the membrane 22 and/or sheathing 14. In yetanother embodiment, the netting 24 may first be secured to the sheathing14 with the membrane 22 then being secured over the netting and/orsheathing.

In at least one embodiment, the netting 24 is laminated to the membrane22 prior to application of the building wrap 20 to the buildingstructure 10. While any suitable lamination process can be used, oneexample of such a lamination process comprises thermal laminating thenetting to the membrane. Techniques other than lamination could beemployed to join the netting 24 and the membrane 27. These techniquesinclude extrusion coating the netting onto the membrane, employing alayer of thermal adhesive, either on the membrane or the netting, and/oremploying a hot melt or other adhesive sprayed onto the membrane and/ornetting.

As can best be seen in FIGS. 1, 3-4 and 6-7, the netting 24 incooperation with the membrane 22 helps to provide a drainage structurecomprising a plurality of generally vertical drainage channels 34. Ifwater condenses, or is otherwise disposed onto the building wrap 20, thechannels 34 will allow the water to drain down the wrap 20 and outsidethe building covering 16.

In the illustrated embodiment, as can be seen in FIGS. 1-4 and 6-7, thenetting 24 comprises strands 30 extending in one direction and strands32 extending in a generally crosswise or transverse direction. When thebuilding wrap 20 is applied to a building structure 10, the strands 30comprise vertical members extending down the building structure and thestrands 32 comprise horizontal members running across the buildingstructure.

When the netting 24 is secured to the membrane 22, the horizontalstrands 32 tend to be offset towards (in some cases attached or bondedto) the membrane 22, thereby with the vertical strands 30 formingchannels 34 facing away from the membrane 22. For instance, in theembodiment illustrated in FIG. 4, the channels 34 face towards theexterior building covering 16 as the membrane 22 is adjacent thesheathing 14. In the alternative embodiment illustrated in FIG. 7, thechannels 34 face towards the sheathing 14.

The strands 30 and 32 are extruded polymeric elongate members whichcross and intersect during extrusion to form the net-like structure. Inat least one embodiment, the strands 30 and 32 are made of the samematerial. In other words, 100% of the strands are made of the samematerial.

In at least another embodiment, strands 30 are made of a differentmaterial than strands 34. In this embodiment, the netting 24 maycomprise 10 to 90 wt. % of the material comprising strands 30 and 90 to10 wt. % of the material comprising strands 32. In other embodiments,the netting 24 may comprise 35 to 65 wt. % of the material comprisingstrands 30 and 65 to 35 wt. % of the material comprising strands 32. Inyet other embodiments, the netting 24 may comprise 45 to 55 wt. % of thematerial comprising strands 30 and 55 to 45 wt. % of the materialcomprising strands 32. In this embodiment, strands 30 may be made of arelatively durable material, such as polypropylene (PP) or polyethylene(PE), and strands 32 may be made of a lower melting point material, suchas ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA) or verylow density polyethylene (VLDPE), which can act as an adhesive forbonding the netting 24 to the membrane 22.

In at least one embodiment, the vertical strands 30 have an averagethickness which is 1.25 to 25 times the average thickness of thehorizontal strands 32. This helps to form the water drainage channels34. In at least another embodiment, the average thickness of thevertical strands 30 is 1.5 to 10 times the average thickness of thehorizontal strands 32. In still yet another embodiment, the averagethickness of the vertical strands 30 is 2 to 5 times the averagethickness of the horizontal strands 32.

In some embodiments, the extruded netting 24 has horizontal strands 32that have an average thickness of 0.5 to 50 mils, in other embodiments0.75 to 15 mils, and in yet other embodiments 1 to 10 mils.

In some embodiments, the extruded netting 24 has vertical strands 32that have an average thickness of 4 to 290 mils, in other embodiments 10to 175 mils, and in yet other embodiments 15 to 100 mils.

In some embodiments, the extruded netting 24 has joints that have anaverage thickness of 5 to 300 mils, in other embodiments 15 to 200 mils,and in yet other embodiments 20 to 150 mils. The joints, as can beenfrom the figures, are integral between the strands 30 and 32. Theintegral joints help to provide a stable netting 24 which preserves therelatively uniform spacing of the strands to provide uniform waterchannels 34.

In at least one embodiment, the strands 30 and 32 are made of anysuitable polymeric material. In at least one embodiment, the strands 30and 32 are made of a non-coated polymeric material. In at least certainembodiments, the polymeric material comprises a relatively durable,relatively high melting point material such as PP or PE.

In some embodiments, as shown in FIG. 5, the strands 30 and 32 include alayer 40 of lamination polymer, such as EVA or EMA, covering at least aportion of a polymeric material (i.e., PP or PE) of the core 42. Thelayer 42 of lamination polymer has a lower melting point than thepolymeric material of the core 42 so that it melts during the laminationprocess to secure the netting 24 to the membrane 22.

The polymeric material may include suitable additives, as are known inthe art. Examples of suitable additives include, but are not necessarilylimited to, colorant, heat stabilizers, UV light stabilizers, flameretardants and anti-microbials.

In at least one embodiment, the extruded netting 24 has a machinedirection strands (horizontal strands 32) per inch (i.e., strand count)of 0.5 to 40 strands/inch, in other embodiments 1 to 20 strands perinch, and in yet other embodiments 5 to 15 strands/inch.

In at least one embodiment, the extruded netting 24 has a crossdirection strands (vertical strands 30) per inch of 0.5 to 30strands/inch, in other embodiments 1 to 15 strands/inch, and in yetother embodiments 2 to 10 strands per inch.

In certain embodiments, the netting 24 will have one side that isgenerally flat. In this embodiment, the side of the netting 24contacting the membrane 22 is generally flat.

In at least one embodiment, the extruded netting 24 can be made by anysuitable reciprocating netting extrusion process. In at least anotherembodiment, the extruded netting 24 can be made by any suitable rotaryextrusion process, where the netting is bias cut, forming machinedirection and cross direction strands. In at least one embodiment, theextruded netting is then uniaxially oriented (i.e., in only onedirection) by any suitable axial orienting process. Suitable examples ofthese processes are well known.

Generally, suitable methods for making the netting 24 comprise extrudingthe polymeric material through dies with reciprocating parts to form thegeneral netting configuration. This creates cross machine directionstrands 30 that cross the machine direction strands 32, which flowcontinuously. After the extrusion, the netting is then typicallystretched in the machine direction only using a speed differentialbetween two sets of nip rollers. Alternatively, after extrusion, thenetting 24 can be stretched in the cross-direction only using a tenterframe. It should be understood, that the above described method is justone of many suitable methods that can be employed to manufacturereciprocating extruded netting 24 in accordance with the presentinvention. In an alternative embodiment, the extruded netting 24 may beoriented in both directions so long as the vertical strands 30 aresubstantially greater in thickness than the horizontal strands 32. Also,while the principles of this invention can apply to any net geometry,the present invention has excellent applicability to square netting andrectangular netting.

An alternative embodiment of a building wrap 120 is shown in FIG. 6. Thebuilding wrap 120 comprises a first membrane 22, a second membrane 122spaced from the first membrane 22 and a netting 24 disposed between thefirst and second membrane 22 and 122. The first membrane 22 is the sameas the first membrane 22 described above, and thus could be permeable orimpermeable. The netting 24 is the same as the netting 24 describedabove. The second membrane 122 can be a permeable membrane or animpermeable membrane, such as the membrane 22 described above. In atleast one embodiment, the first membrane 22, which is adjacent thesheathing 14 when in use, is a vapor permeable membrane and the secondmembrane 122, which is adjacent the exterior covering 16 when in use, isan impermeable membrane.

The building wrap 20 made in accordance with the present invention hasmany potential uses, such as wrapping houses and commercial buildings,as well as under layments for roofs.

In one embodiment, the building wrap 20 may be secured to sheathing 14via any suitable fastener such as nails, screws or staples. In analternative embodiment, the wrap 20 may be secured to the framestructure 12, if no sheathing is present. In at least one embodiment,the components of the wrap 20 may be applied to the building structurein separate steps wherein the membrane 22 is secured to the buildingstructure 10 first via any suitable fastener and then the netting 24 issecured to the membrane by any suitable fastener.

The present invention may be further appreciated by consideration of thefollowing, non-limiting examples, and certain benefits of the presentinvention may be further appreciated by the examples set forth below.

While embodiments of the invention have been illustrated and described,it is not intended that these embodiments illustrate and describe allpossible forms of the invention. Rather, the words used in thespecification are words of description rather than limitation, and it isunderstood that various changes may be made without departing from thespirit and scope of the invention.

1. A water management building wrap comprising: a membrane having afirst side and a second side; and an extruded polymeric nettingstructure secured to one of the sides of the membrane, the nettingstructure including a plurality of generally vertical members having afirst average thickness and spaced apart from each other such thatadjacent pairs of the generally vertical members form boundaries for agenerally vertical water drainage channel, the netting structure furtherincluding a plurality of generally horizontal members extending betweenand attached to the generally vertical members and having a secondaverage thickness less than the first thickness, the netting structurehaving integral joints at intersections of the generally verticalmembers and the generally horizontal members, the joints providingdimensional stability to maintain the orientation of the generallyvertical members and form stable vertical water drainage channels, thenetting structure having a core of a first material and an outer layerof a second material surrounding at least a portion of the core.
 2. Thebuilding wrap of claim 1, wherein the melting point of the outer layeris lower than the melting point of the core.
 3. The building wrap ofclaim 2, wherein the membrane is permeable.
 4. The building wrap ofclaim 3, wherein the netting is secured to the permeable membrane bybeing laminated to the permeable membrane.
 5. The building wrap of claim4, wherein the outer layer of the netting structure is melted and bondedto the permeable membrane to cause the netting to be laminated to thepermeable membrane.
 6. The building wrap of claim 3, wherein thepermeable membrane has a thickness of 1 to 75 mils.
 7. The building wrapof claim 2, wherein the membrane is water resistant.
 8. The buildingwrap of claim 1, wherein the membrane comprises a first membrane, andthe building wrap further comprises a second membrane disposed over aside of the netting opposite the first membrane.
 9. A netting usablewith a membrane to provide a water management building wrap havingvertical water drainage channels, the netting comprising: an extrudedpolymeric netting structure securable to one side of the membrane, thenetting structure including a plurality of generally vertical membersspaced apart from each other such that adjacent pairs of the generallyvertical members form boundaries for a generally vertical water drainagechannel, the netting structure further including a plurality ofgenerally horizontal members extending between and attached to thegenerally vertical members, the netting structure having integral jointsat intersections of the generally vertical members and the generallyhorizontal members, the joints providing dimensional stability tomaintain the orientation of the generally vertical members and formstable vertical water drainage channels, the netting structure having acore of a first material and an outer layer of a second materialsurrounding at least a portion of the core.
 10. A method of forming awater management building wrap for use between a sheathing of a buildingand an exterior building covering, the method comprising: disposing apermeable membrane over at least a portion of the sheathing, themembrane having a first side and a second side, the first side, when themembrane is disposed on the sheathing, facing the sheathing; anddisposing an extruded polymeric netting structure over the second sideof the membrane, the netting structure including a plurality ofgenerally vertical members having a first thickness and spaced apartfrom each other such that adjacent pairs of the generally verticalmembers form boundaries for a generally vertical water drainage channel,the netting structure further including a plurality of generallyhorizontal members extending between and attached to the generallyvertical members and having a second thickness less than the firstthickness, the netting structure having a core of a first material andan outer layer of a second material surrounding at least a portion ofthe core, the netting structure having integral joints at intersectionsof the generally vertical members and the generally horizontal members,the joints providing dimensional stability to maintain the orientationof the generally vertical members and form stable vertical waterdrainage channels.
 11. The method of claim 10 further comprising,heating the netting structure to melt the outer layer, thereby adheringthe netting structure to the permeable membrane.
 12. The method of claim10 further comprising, disposing a second membrane over a side of thenetting structure opposite the permeable membrane.
 13. A building wrapfor managing water drainage from an exterior wall of a building, thewrap being for use between a frame and an exterior covering of thebuilding, the building wrap comprising: a first membrane formed of asheet of permeable material and being disposable over the frame; and anetting formed of a unitary polymeric extrusion, the netting disposedover the first membrane, the netting having a series of generallyvertical members and a series of generally horizontal members havingintegral joints at intersections between the generally vertical membersand the generally horizontal members, the netting having an array ofwater drainage channels.
 14. The building wrap of claim 13, wherein thenetting includes a core of a first material and an outer layer of asecond material surrounding at least a portion of the core.
 15. Thebuilding wrap of claim 14, wherein the melting point of the outer layeris lower than the melting point of the core.
 16. The building wrap ofclaim 15, wherein the netting is laminated to the first membrane. 17.The building wrap of claim 15, wherein the netting is laminated to thefirst membrane by melting the outer layer of the netting.
 18. Thebuilding wrap of claim 13, wherein the first membrane has a thickness of1 to 75 mils.
 19. The building wrap of claim 14, further comprising asecond membrane disposed over a side of the netting opposite the firstmembrane.
 20. The building wrap of claim 19, wherein the first membraneis permeable and the second membrane is not permeable.